Processing machines for plate-shaped work pieces in which the work pieces are conveyed through a conveyor system and then undergo processing by a processing device which is arranged alongside the conveying route are known from the prior art. EP 1 464 470 A2 may be referred to as an example.
Such machines have undergone further development in recent years to such an extent that it has been possible to increase the processing or throughput speeds more and more. Here, however, it should be noted that the end user frequently does not use the machine to process runs of the same work pieces, but rather feeds in a variety of work pieces as required and prepared. These differences relate not only to the shape of the work pieces, but in particular also to the edge materials (or coatings) which have been applied in particular to the narrow or side faces of the work piece in a possible previous processing step.
In order to ensure a pleasing appearance in the finished work piece, this edge material must be taken into consideration for the further processing of the work piece in a processing machine. Thus, for example, “thick edges” require different processing than “thin edges”. Inadequate or insufficient consideration of these influencing factors results in rejects.
In this regard, the state of the art suggests mechanical sampling of the neuralgic areas of the work piece for further processing, among other things. As an alternative, the storage of the relevant data under a code which is applied to the work piece and is then read accordingly by the processing machine is known. However, both measures are prone to error, particularly at high machine rates, and are labour-intensive to implement in practice.
EP 1 464 470 A2 suggests a machine in which the opto-electronic devices are used for imaging acquisition of the narrow side profiles. The corresponding profiles of the edges are then reconstructed at least approximately through appropriate image processing and analysis. This, according to EP 1 464 470 A2, allows commands for trimming of protruding edge material in the form of so-called cutting trajectories to be issued to a respective processing device.
Even such methods reach their limits if the processing speed is to be further increased. The acquisition of an image in the form of a type of data cloud, its processing and the calculation of the complete profile is a very complex undertaking which unavoidably takes a certain amount of processing time. At the desired conveyor speeds of multiple metres per minute, this is no longer practical because the data processing is simply no longer able to keep up with the machine cycle.